In the field of ink jet printing, it has been one practice to employ disposable pens which are removably mounted in a carriage of an ink jet printer. One such type of pen is disclosed and claimed in copending application Ser. No. 880,774 of Jeffrey Baker et al., filed Jul. 1, 1986, now Pat. No. 4,771,295 assigned to the present assignee and incorporated herein by reference. When the volume of ink within the pen body housing is depleted, the pen is removed from the pen carriage of the printer and replaced with a new one.
In order to extend the useful life of the pen to that of its associated printhead, several approaches have been suggested wherein the ink reservoir within the pen body housing is periodically refilled until such time that some failure mode occurs in the pen. These approaches have included the use of an off board ink supply, meaning that the larger ink supply is positioned at a location remote from the pen and pen carriage assembly of the ink jet printer.
All of these prior art approaches known to me require either some active pumping device or the utilization and mechanical control of gravitational forces (a positive pressure between off board supply and pen body) in order to move the ink from the off board ink supply and into an ink reservoir within the pen body housing. For example, one such active pumping device is disclosed in U.S. Pat. No. 4,368,478 issued to Koto et al. Both of these prior approaches possess certain inherent disadvantages which are related to the provision of either an active pumping device or the utilization of gravitational forces. In contrast thereto, the passive ink supply system according to the present invention overcomes most if not all of these inherent disadvantages of known prior art ink supply systems, and the exact manner in which this is accomplished will become better understood in the following description of the accompanying drawings.